As a method for forming a color pixel in manufacturing a color filter of a liquid crystal display element, a solid-state image sensing element, and the like, a dyeing method or a dye-dispersion method employing a dye for a colorant, a pigment-dispersion method using a pigment, an electrodeposition method, a printing method, and the like, has been known. In recent years, as characteristics of the color filter, enhancement of brightness and contrast has particularly been required. According to the pigment-dispersion method using a pigment, because the pigment has higher heat resistance and light resistance as compared with a dye, a color pixel having less deterioration at heating process in manufacturing a panel, and also having high long-term reliability can be obtained. Therefore, at present, the pigment-dispersion method has become the mainstream. However, when a pigment was used, because the pigment itself has relatively large particle size, there was a problem of decrease in contrast caused by light scattering. Although an attempt has also been made to micronize the pigment, there is a limit also in micronization, and it has also been a problem to secure dispersion stability of the micronized pigment.
On the other hand, as a method which is capable of resolving these problems, a method for forming the color pixel using a dye has been studied at present. When the dye is used, contrast is enhanced because light scattering is suppressed. However, because the dye has lower heat resistance as compared with a pigment, and sublimation depending on the type, there were problems such as reduction in brightness, fading and hue change. Therefore, to use the dye, it has been required to resolve this problem.
On the other hand, as a yellow dye for the color filter, a cyanine-based coloring compound, a barbituric acid azo-based coloring compound (PATENT LITERATURE 1), an azo-based coloring compound (PATENT LITERATURE 2), a pyridone azo-based coloring compound (PATENT LITERATURE 3), and the like, have usually been used. However, an azo group in the azo-based compounds has been known to inhibit a radical reaction. Accordingly, in the case of producing the color filter using the azo-based compound, a cored film having sufficient strength may not be obtained, due to not proceeding of a polymerization reaction.
In addition, a dye having an absorption band at a certain specific wavelength blocks out light having harmful wavelength, or reduces transmittance thereof. Accordingly, addition thereof to various products is capable of acquiring a role as a filter. For example, a dye which cuts blue light (visible rays of 380 to 500 nm), known as a wavelength range harmful to eyes, can be used suitably for spectacle lens, and a peripheral material such as a frame and a cover thereof. As an example, there has been known a dyeing method by permeation or diffusion of a dye on to a lens surface (PATENT LITERATURE 4). However, because it is surface fabrication, uniform dyeing may not be attained in some cases. In addition, there is such a different method as preparing a plastic lens for blocking out UV up to 400 nm, by mixing an UV absorbent into a specified monomer and polymerizing it (PATENT LITERATURE 5). However, because the UV absorbent is not directly bonded to a monomer, there was a problem of easily generating dyeing irregularity in polymerization, and the like.